The present invention relates to the field of appliances for the preparation of coffee infusions, more particularly espresso-type appliances comprising a coffee bean mill.
It relates more particularly to a method for counting the number of revolutions of a grinding burr of a coffee mill driven in rotation by an electric motor.
In appliances of the aforementioned type, the quantity of ground coffee dispensed by the burr is a function of the number of revolutions made by the latter. It is therefore important to accurately determine the number of revolutions made by the burr in order to dispense a predetermined dose of ground coffee during a drink production cycle.
An appliance comprising a coffee mill driven by an electric motor is known from the document FR 2648035. The number of revolutions made by the burr is determined by means of a sensor and a command for shutting off the motor is issued when a predetermined number of revolutions has been reached. The sensor, for example a Hall effect sensor, detects the passage of a marker, for example a magnetic marker, placed on a toothed wheel of a reduction gear placed between the motor and the mill.
This known method for counting the number of revolutions has the drawback of requiring a sensor equipped with jumper wires connected to a measuring circuit and a marker attached to a toothed wheel of the reducing gear. This configuration results in a high production and assembly cost and can induce reliability problems linked to a misalignment of the sensor with respect to the marker or to breaks in the jumper wires.